In general, light sensor elements, or pixels, can be subjected to different brightness and light intensity. Each pixel reaches a saturation level at a different time based on the detected brightness. In other words, the slope of each pixel will vary depending on the amount of light reaching the pixel, where the slope is its voltage plotted over time, e.g., the voltage as the y-axis and the time as the x-axis.
Accordingly, a pixel with a greater slope reaches saturation level faster in comparison to other pixels. When the saturation level during the integration time of a pixel is reached the collection of brightness information for that pixel stops.